As a transmitting/receiving system of the related art, products configured by assembling separate parts have been mainly used. However, recent studies have been conducted on system on package (SOP) products which configure the transmitting/receiving system of a millimeter wave band in a single package, and some products are commercialized. A technology for providing the single package product has been developed together with a multi-layer substrate process technology which stacks a dielectric substrate, such as low temperature co-fired ceramic (LTCC) and liquid crystal polymer (LCP).
In an environment, such as the LTCC process and the LCP process, a patch antenna having a planar characteristic is mainly used. The patch antenna is disadvantageous in that its bandwidth generally narrows below 5%. To address the narrow bandwidth, the bandwidth is expanded by generating multiple-resonances by adding a parasitic patch on the same plane as the patch antenna serving as a main radiator, or by inducing multiple-resonances by stacking two or more patch antennas.
The bandwidth can increase using a plurality of patches. However, using such a multiple-resonance technology, a radiation pattern of the antenna may be different for each resonant frequency and the antenna characteristic due to process errors may change more considerably than the single resonance antenna. Hence, in order to increase efficiency and to secure a wider bandwidth of the antenna, a dielectric resonator antenna (DRA) may be used. It is known that the DRA has excellent characteristics in terms of the bandwidth and the efficiency, compared with the patch antenna of the related art having the multiple-resonances.
Although the DRA is frequently used in order to overcome drawbacks of the patch antenna, it requires a separate dielectric resonator outside of a substrate. As a result, it is more difficult to manufacture the DRA than the patch antenna which is fabricated through the single process. In addition, the DRA can generate the multiple-resonance in response to the size increase of the dielectric resonator (e.g., a length in a direction not affecting the resonant frequency) and thus secure a wider bandwidth, but is disadvantageous in that its radiation pattern is skewed within the bandwidth.
Therefore, a need exists for an antenna apparatus having multiple-resonances.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.